Transfection of VEGF165 genes into endothelial progenitor cells and in vivo imaging using quantum dots in an ischemia hind limb model

Endothelial progenitor cells (EPCs) were transfected with fluorescently labeled quantum dot nanoparticles (QD NPs) with or without VEGF165 plasmid DNA (pDNA) to probe the EPCs after in vivo transplantation and to test whether they presented as differentiated endothelial cells (ECs). Bare QD NPs and QD NPs coated with PEI or PEI + VEGF165 genes were characterized by dynamic light scattering, scanning electron microscopy, and atomic force microscopy. Transfection of EPCs with VEGF165 led to the expression of specific genes and proteins for mature ECs. A hind limb ischemia model was generated in nude mice, and VEGF165 gene-transfected EPCs were transplanted intramuscularly into the ischemic limbs. At 28 days after transplantation, the VEGF165 gene-transfected EPCs significantly increased the number of differentiated ECs compared with the injection of medium or bare EPCs without VEGF165 genes. Laser Doppler imaging revealed that blood perfusion levels were increased significantly by VEGF165 gene-transfected EPCs compared to EPCs without VEGF165. Moreover, the transplantation of VEGF165 gene-transfected EPCs increased the specific gene and protein expression levels of mature EC markers and angiogenic factors in the animal model.